In recent years, the proliferation of ballistic missile systems and weapons of mass destruction has increased. Currently it is estimated that there are more than 20 countries that possess ballistic missiles.
Clearly, the threat today is much different than that of the Cold War era, with a more complicated and dynamic geopolitical environment producing asymmetric threats. As a result, the United States (US) has placed highest priority on developing and fielding an effective and robust Ballistic Missile Defense System (BMDS).
The Missile Defense Agency (MDA) is charged to develop, test and prepare to field a missile defense system for the US. To accomplish this, MDA must develop weapons, sensors, communication systems and platforms that work in conjunction to detect, engage and disrupt ballistic missiles in all phases of flight—referred to as a “layered defense.”
All ballistic missile trajectories consist of three phases—boost, midcourse and terminal. The boost phase is defined as the part of the missile's flight from the time of launch until it stops accelerating under its own propulsion system, typically the first 60 to 300 seconds of flight. While it is ideal to destroy the missile in the boost stage, the window of opportunity is relatively small, and the missile-defense elements (Airborne Laser) must be deployed near the launch location.
The midcourse phase of a ballistic missile trajectory follows a more predictable flight path, with the missile traveling essentially exo-atmospherically, or in very low Earth orbit. There is more time for BMDS elements to track and engage the target, but the missile can also deploy countermeasures at this phase. Midcourse missile defense elements (Aegis BMD) provide protection for large regions.
The terminal phase of flight starts when the missile re-enters the Earth's atmosphere, generally lasting less than 60 seconds. Terminal-phase missile defense (THAAD, PAC-3) provides very localized protection. Taken together, this layered-defense strategy gives BMDS the most opportunities to thwart a ballistic missile attack.
Just as space situational awareness (SSA) is the cornerstone of space control, battlespace awareness is the critical element of BMDS. Complete battlespace awareness requires a network of sensors that can identify and track all ballistic missile threats targeted at US forces and territories, as well as those of its allies.
Currently BMDS relies heavily on radar systems and space-based IR systems (launch detection). Current defense systems may not be sufficient to overcome enemy countermeasures (i.e., decoys). Clearly, as missiles and countermeasures become more advanced, needs exist for more advanced sensor and weapons systems to effectively mitigate the threat.
Needs exist for a high speed accurate detection and tracking system which overcomes conventional systems having insufficient speed and accuracy.